Generally speaking, the rehearsal will be conducted by the host, and the effect will be better on the wedding day. If the host can't be present for special reasons, the personnel of the wedding company, such as the supervisor, can rehearse for the couple. Then ask the second supervisor to be quite familiar with the wedding process and the host's words. Rehearsal is mainly to teach new people movements, positions, postures and so on. And newcomers don't have to recite the process.